The push button switch with scissors-type plunger is broadly used in notebook type computer.
U.S. Pat. Nos. 5,278,371, 5,746,308, 5,512,719, 5,457,297, 4,433,225, 4,580,022, 4,902,862, 5,280,147, 5,329,084, 5,382,762, 5,399,822, 5,463,195, 5,466,901, 5,504,283, 5,519,569, 5,512,719, 5,278,372 and 5,278,374 respectively disclose key switch of scissors-type plunger.